The invention relates to a method for producing a bird protection device according to the preambles of the independent claims and a bird protection device.
With the increasing use of glass in building shells, the number of bird strikes increases dramatically worldwide. Birds do not recognize the glass obstacles which appear to them as transparent and suffer serious injuries when flying against the glass facades. “Around 250,000 birds die every day in Europe due to impact on windows, glass doors and facades. Until recently, the solutions from the glass industry for the problem “bird strike” were totally inadequate. For example, the adhesively mounted silhouettes of birds of prey, which are still in use today, are completely ineffective as a “warning signal”.”[www.ornilux.de].
Bird protection devices are known in the art which can be divided into two categories.
The first category includes devices that may be recognized by both birds and humans. Technical embodiments include for example glasses, which are provided with structures in the form of dots, lines or grids in the visible spectrum (380 nm to 780 nm) (WO 2004/070148 A2, Eckelt: Prospectus 4bird, www.eckelt.at).
The second category includes devices which are intended to protect birds from bird strikes and are, if possible, imperceptible by the human eye so as not to interfere with the aesthetics of the building. Here, the prior art focuses on the formation of structures in the ultraviolet region (UV-A=315 nm to 380 nm) which can be perceived by the bird's eye, but cannot be perceived by the human eye. For example, EP 1110450 B1 describes a bird protection device wherein the window pane is provided with a film that has higher absorptivity or reflectivity in the UVA wavelength range and is thus not visible to humans, but can be perceived by the bird. DE 102007028543 A1 describes different ways to form structures in the glass surface through incorporation of metal ions, which are visible for birds in the UV-A range but are invisible for humans. Furthermore, attempts have been made to design the bird protection structures by way of their dimensions so that they are hardly noticeable by humans. EP 1319335 B1 describes, for example, line-like structures with a main dimension than 0.5 mm, preferably smaller than 0.1 mm, which are therefore nearly imperceptible for humans.
While devices of the aforementioned type are known in the art, their implementation through process engineering solution has thus far only rarely been cited. For example, the description in DE 10 2007 028 543.6 discloses a multistep process wherein in the first step, a metal ion-containing paste is applied to the glass surface via a printing process; in the second step, the paste is dried for about 4 hours by heat treatment at about 70° C.; in the third step, diffusion of the metal ions into the glass surface is achieved by heat treatment of the entire glass body at about 500° C. for about 45 min; and subsequently in the fourth step, the excess paste is removed by a cleaning process. This example shows that the production of bird protection devices, in particular of those in the second category, has previously been attained in an unsatisfactory manner. The extensive, lengthy and complex producing process is costly and thus results in a bird protection device having high production costs. This inhibits the extensive application of such bird protection devices.
Accordingly, it is the object of the present invention to provide a lower-cost producing process for bird protection devices, which preferably also increases the contrast of the optical structures of the bird protection device.